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Comment by alkonaut | Hacker News Reader

I was also very curious how they managed to get my '09 "fixed" somehow via a simple software patch. I would have understood it if it had lost 20% performance or got 20% higher fuel consumption - but that didn't happen.

So: if it was that easy to fix legally why did they cheat in the first place??

Of course it can't be that easy. So of course my car is still polluting over the limit. And I think this is a story that isn't getting the coverage it needs. A proper fix for my car would have been to install an AdBlue system into it, at great cost. Had they been forced to do that - or buy back the car - they would be in serious financial trouble.

That also answers why the German government is giving them some leeway here: it's not exactly in their interest to kill Volkswagen.

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> That also answers why the German government is giving them some leeway here: it's not exactly in their interest to kill Volkswagen.

While the federal government does not have a direct stake (apart from all the tax euros), the fine state of Lower Saxony holds a 20 % share (which actually causes the MP and his economics minister to always be on the board of directors).

The country has a huge stake regardless since they likely pay unemployment benefits if they were to go under etc.

Interesting. Does that mean they could have been aware of the problem (from being on the board), before it became public knowledge?

Why would prosecuting the executives kill WV, though?

If VW is forced to make all regulations-breaching cars to be compliant and compensate the owner for down-time and loss in fuel-efficiency or performance, that might mean the end to VW. VW is touched softly, just like Intel, for example. I think both the car and the IC industries should be more regulated, and the regulations should be effectively enforced.

As far as I know, they did have to make the cars compliant. At least my colleague, who had an affected Skoda, got it "fixed" for free, including a temporary replacement car.

If there was a demand that the "fixed" cars were actually tested and were now under the limit while not losing more than say 5% in economy or power (or else owners would have to be compensated) it would likely find that the cars fail one or more of these requirements.

I believe it's now a middle ground: cars lost "only" about 5-10% performance/fuel eco, and they are still only half way to the NOx limit.

"if it was that easy to fix legally why did they cheat in the first place??"

Your car did take a performance hit and fuel economy hit. Not a big one, but enough to make it less competitive during instrumented tests by journalists. Tests are showing about 5-6% fuel economy hit which is not trivial, and also engine performance hit in higher RPM band.

Luckily, most car buyers don't push their cars enough to notice.

There are a lot of different parameters they can change, but the main ones are turbo boost and injection time. It is easy to find one set of values for each power output request that will make the engine run. Now you optimize. The combinations that is over the limits might not be that different than the values that is over the limits, so it is just a matter of trying them all to see what happens. This is done as an educated guess and refinement: we don't know exactly what any gives set will produce, but we have a good guess.

It totally can be that easy, though. Imagine the software in the car has the following pseudo-code…

    if (emissions_test_running()) {
       run_efficiently();
    } else {
       business_as_usual();
    }

… which could get replaced with …

    run_efficiently();

No, you have that backward a bit: the NOx emissions are high when the car runs efficiently (high compression/temperature)

So you can make the engine run at high temp, do 5L/100km and output 200hp, but with lots of NOx produced

Or you can run it cooler, with less NOx produced, but then it does 6L/100km and ouputs 175hp (say)

So basically the bad code was

    if (under test)
       run_cool_inefficient_lowNOx
    else
       run_hot_efficient_highNOx

The reason why many diesel manufacturers cheated is because the numbers for diesels are only good if you run hot. All that low consumption, high power etc comes from its ability to run hot, but then it spews NOx.

This was made worse by EU regulations that focused 100% on CO2 - which is proportional to consumption only.

In order to sell cars in the EU they needed models that stayed under 120g/km CO2 (say 5L/100km) and of course they couldn't be lower power than the competition, and to stay under price limits for company purchases they needed models that stayed under the price limit where they could fit AdBlue systems

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